import java.util.*;
class Solution {
    public void reverseString(char[] s) {
        int r = s.length-1;//注意数组越界
        char cr=' ';
        for(int i=0;i<=(s.length-1)/2;i++){
           cr=s[i];
           s[i]=s[r-i];
           s[r-i]=cr;
        }
        for(int i=0;i<s.length;i++){
            System.out.print(s[i]);
        }
    }
}